FirebaseRecyclerAdapter get null value

Question

I stuck with the following problem. When I tried to get value from FirebaseRecyclerAdapter I get null, only key the this that I can see. Please review my code:

 public abstract class TabFragmentLists extends Fragment {

    private DatabaseReference mDatabase;

    private FirebaseRecyclerAdapter<Post, PostViewHolder> mAdapter;
    private RecyclerView mRecycler;
    private LinearLayoutManager mManager;

    public TabFragmentLists() {
        // Required empty public constructor
    }


    @Override
    public View onCreateView (LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {
        super.onCreateView(inflater, container, savedInstanceState);
        View rootView = inflater.inflate(R.layout.fragment_tab_lists, container, false);

        mDatabase = FirebaseDatabase.getInstance().getReference();
        mRecycler = (RecyclerView) rootView.findViewById(R.id.messages_list);
        mRecycler.setHasFixedSize(true);

        return rootView;
    }

    @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);

        // Set up Layout Manager, reverse layout
        mManager = new LinearLayoutManager(getActivity());
        mManager.setReverseLayout(true);
        //mManager.setStackFromEnd(true);

        mRecycler.setLayoutManager(mManager);

        // Set up FirebaseRecyclerAdapter with the Query
        Query postsQuery = getQuery(mDatabase);
        mAdapter = new FirebaseRecyclerAdapter<Post, PostViewHolder>(Post.class, R.layout.item_post,
                PostViewHolder.class, postsQuery) {
            @Override
            protected void populateViewHolder(final PostViewHolder viewHolder, final Post model, final int position) {
                final DatabaseReference postRef = getRef(position);

                // Set click listener for the whole post view
                final String postKey = postRef.getKey();

                viewHolder.bindToPost(model, new View.OnClickListener() {
                    @Override
                    public void onClick(View postView) {
                        Log.e("OnClick","== Bind===");
                    }
                });
            }
        };

        mRecycler.setAdapter(mAdapter);
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        if (mAdapter != null) {
            mAdapter.cleanup();
        }
    }

    public String getUid() {
        return FirebaseAuth.getInstance().getCurrentUser().getUid();
    }

    public abstract Query getQuery(DatabaseReference databaseReference);
}

PostViewHolder

public class PostViewHolder extends RecyclerView.ViewHolder {

    public TextView messsageView;
    public PostViewHolder(View itemView) {
        super(itemView);

        messsageView = (TextView) itemView.findViewById(R.id.post_message);
    }

    public void bindToPost(Post post, View.OnClickListener starClickListener) {
        //null and crash
        Log.e("Post", String.valueOf(post.getMessage())); 
        messsageView.setText(post.getMessage());
    }
}

Post class

@IgnoreExtraProperties
public class Post {

    public String message;
    public String getMessage() {
        return message;
    }

    public void setMessage(String message) {
        this.message = message;
    }


    public Post() {
        // Default constructor required for calls to DataSnapshot.getValue(Post.class)
    }

    public Post(String message) {
        this.message = message;
    }

    @Exclude
    public Map<String, Object> toMap() {
        HashMap<String, Object> result = new HashMap<>();
        result.put(PostKeys.kMessage.toString(), message);
        return result;
    }

}

And here is DB structure

Would appreciate any hint. Thanks

EDIT

public class TabFragmentPosts extends TabFragmentLists {

    public TabFragmentPosts() {
        // Required empty public constructor
    }

    @Override
    public Query getQuery(DatabaseReference databaseReference) {
        // All my posts
        return databaseReference.child("post");
    }

}

This exactly what I eventually have

E/LIST dataSnapshot: DataSnapshot { key = -KOgO2hC9Fh_vhe1kh1z, value = null }

Answer 1

Finally, found the problem class Post should have exact the same name of variables (taking into account uppercase/lowercase)

@IgnoreExtraProperties

public class Post {

    public String Message; // HERE IS THE PROBLEM WAS

    public Post() {
        // Default constructor required for calls to DataSnapshot.getValue(Post.class)
    }

    public Post(String Message) {
        this.Message = Message;
    }

    @Exclude
    public Map<String, Object> toMap() {
        HashMap<String, Object> result = new HashMap<>();
        result.put("Message", Message);
        return result;
    }
}

Thanks to all who tried to help!!! Appreciate it!

Answer 2

Unless I've misread your code it looks like you've set your DatabaseReference incorrectly - you're currently just pointing it to your base Firebase reference but you need to direct it to your 'post' path.

You'll need to add a .child("post") to your mDatabase property.

Answer 3

First check the security rules, whether you have enabled permissions for it or not...If not enable permissions...In the below link find how to set permissions...https://firebase.google.com/docs/database/security/quickstart